Users of Origin, the game distribution platform of Electronic Arts (EA), are vulnerable to remote code execution attacks through origin:// URLs, according to two security researchers.
Luigi Auriemma and Donato Ferrante, the founders of Malta-based security consultancy firm ReVuln, disclosed the security issue Friday during a talk at the Black Hat Europe 2013 conference in Amsterdam.
The vulnerability allows attackers to execute arbitrary code on Origin users' computers by tricking them into visiting a malicious website or clicking on a specially crafted link, the researchers said. In most cases the attack will be automatic and require no user interaction, they said.
When the Origin client is installed on a computer, it registers itself as the handler for origin:// protocol links, which are used to launch games -- including with command line options -- or to initiate other actions through the client.
Some games have command line options that allow the loading of additional files. For example, the researchers demonstrated the Origin link attack against the new "Crysis 3" game, which supports a command option called openautomate.
Openautomate is a feature that allows users to test the performance of their graphics card in "Crysis 3" using the Nvidia benchmark framework. The command is followed by the path to a DLL (dynamic link library) file that's then loaded by the "Crysis 3" process.
The researchers found a way to craft origin:// links that instruct the Origin client to open "Crysis 3" with the openautomate command followed by a path to a malicious DLL file hosted on a network or WebDAV share. A separate command option can be included in the URL to make "Crysis 3" open silently in the background without users seeing any windows.
Attackers could then trick users into visiting a website containing a piece of JavaScript code that forces their browsers to open the specially crafted link.
When an origin:// link is opened for the first time in a browser, users will be asked if they want to open it with the Origin client, which is the registered handler for this type of URL. Some browsers will display the full URL path or a part of it, while other browsers won't display the URL at all, the researchers said.
The confirmation prompts displayed by browsers provide users with the option to always open origin:// links with the Origin client. Most gamers have probably already selected this option so that they're not bothered with confirmation dialogs every time they click on an origin link, which means that for them the attack will be fully transparent, the researchers said.
The vulnerability is almost identical to one found by the same researchers last year in Valve's Steam online game distribution platform. That flaw allowed the abuse of steam:// protocol links in the same way.
The Steam vulnerability was reported in October 2012 but has yet to be fixed, the researchers said. Fixing it would probably require considerable changes to the platform because it results from a design flaw, they said. The researchers don't expect EA to fix the origin link issue any time soon either.
The attack is not limited to "Crysis 3." It also works for other games that have similar command line features or some local vulnerabilities, the researchers said. The flaw essentially provides a way to remotely abuse features or security issues that would otherwise only be exposed to local attacks, they said.
Auriemma and Ferrante never disclose the vulnerabilities they find to the affected software vendors, so they did not alert EA about the flaw before presenting it at Black Hat.
The researchers published a white paper on their website that explains the issue in more detail and proposes a way to mitigate the attacks. The mitigation involves using a specialized tool called urlprotocolview to disable the origin:// URL.
The side effect of doing this will be that launching games using the desktop shortcuts or their executable files will no longer work. However, users will still be able to launch the games from inside the Origin client.